"The government of the Islamic Republic of Iran condemns ... this inappropriate and offensive action," First Vice-President Mohammad Reza Rahimi said, according to the Mehr news agency.

"Certainly it will search for, track, and pursue this guilty person who ... has insulted 1.5 billion Muslims in the world," he said.

The Islamic Republic's founder, Ayatollah Ruhollah Khomeini, condemned to death the Indian-born British novelist Salman Rushdie in 1989 for his novel "The Satanic Verses," saying its depiction of the Prophet Mohammad was blasphemous.

Iranian officials have demanded that the United States apologize to Muslims for the movie, saying it is only the latest in a series of Western insults aimed at Islam's holy figures.

Rahimi did not give details on how Iran would pursue the makers of the film in his remarks, which the Iranian Students' News Agency said he had made at a cabinet meeting on Sunday.

The US ambassador to Libya,
Christopher Stevens, and three other Americans were killed in Benghazi, Libya, last Tuesday and several other people have died in protests around the Muslim world against the video entitled "Innocence of Muslims."

The identity of those directly responsible for the film is still murky. Clips of the film posted online since July have been attributed to a man named Sam Bacile, which two people linked to the film have said was probably an alias.

Nakoula Basseley Nakoula, 55, a Coptic Christian widely linked to the film in media reports, was voluntarily questioned on Saturday by US authorities investigating possible violations of his probation for a bank fraud conviction.

An Iranian religious foundation said on Saturday it was increasing its reward for the killing of Rushdie, though he had nothing to do with the film, offering a total of $3.3 million for anyone who carried out Khomeini's death sentence.